The present invention relates to conveyor systems, and more specifically to drive systems for unit handling roller conveyor systems.
Unit handling roller conveyor systems generally comprise sections, or zones, made up of conveyor frames supporting individual rollers. The rollers of each zone are driven by a motor and transport items from one end of the zone to the other. Each zone may have separate controls with the zone and associated controls interconnected with other zones to form a larger conveying system. Further, these systems may be configured to operate in various modes depending on the physical characteristics of the products being conveyed and the needs of the end users of the conveyor systems.
For instance, a common operating mode is referred to as zero-pressure accumulation (“ZPA”) wherein an individual parcel being conveyed is the only parcel that is permitted to occupy a single zone, or occasionally multiple zones depending on the relative sizes of the parcel and the zones. In this mode, typically the parcels are prevented from coming into contact with the parcels in adjacent zones making it suitable for conveying products that are fragile, of particularly high value or that have to be individually sorted or weighed at some point further along the system.
Another common mode is referred to as low-pressure accumulation (LPA) wherein the conveyor system is used for in-process storage and the goal is to allow a given number of zones to provide storage for the greatest possible number of parcels without causing damage to the parcels.
Yet another common mode is pure transport where a section of conveyor comprised of multiple zones simply runs continuously in order to transport the parcels from one end to the other without regard for issues related to spacing or contact between parcels.
It is not uncommon for systems to include an inclined section of conveyor that requires additional torque or to have a junction where parcels have to be accelerated from a complete stop to full speed in a very short distance or very short period of time in order to properly merge with parcels on an intersecting section of conveyor.
Yet another operating mode is where the entire system needs to be monitored and controlled from a single computer in order to track the location of individual parcels or to facilitate the identification of trouble spots or failure modes within the system.
Given the extreme variability of the needs of the end users, it is highly desirable for a conveyor manufacturer to have a single set of component parts in inventory from which it is possible to readily configure the systems required by customers in order to satisfy their needs quickly and at a competitive price.